Akt2 phosphorylates Synip to regulate docking and fusion of GLUT4-containing vesicles

We have identified an unusual potential dual Akt/protein kinase B consensus phosphorylation motif in the protein Synip (RxKxRS97xS99). Surprisingly, serine 97 is not appreciably phosphorylated, whereas serine 99 is only a specific substrate for Akt2 but not Akt1 or Akt3. Although wild-type Synip (WT-Synip) undergoes an insulin-stimulated dissociation from Syntaxin4, the Synip serine 99 to phenylalanine mutant (S99F-Synip) is resistant to Akt2 phosphorylation and fails to display insulin-stimulated Syntaxin4 dissociation. Furthermore, overexpression of WT-Synip in 3T3L1 adipocytes had no effect on insulin-stimulated recruitment of glucose transporter 4 (GLUT4) to the plasma membrane, whereas overexpression of S99F-Synip functioned in a dominant-interfering manner by preventing insulin-stimulated GLUT4 recruitment and plasma membrane fusion. These data demonstrate that insulin activation of Akt2 specifically regulates the docking/fusion step of GLUT4-containing vesicles at the plasma membrane through the regulation of Synip phosphorylation and Synip–Syntaxin4 interaction

Continuous or Transient High Level of Glucose Exposure Differentially Increases Coronary Artery Endothelial Cell Proliferation and Human Colon Cancer Cell Proliferation

We studied effect of high glucose levels on coronary artery endothelial cell proliferation and human colon cancer cell proliferation. To examine the long-term effect of glucose exposure on cell growth, cells were cultured for 14 days in the absence or presence of 183 mg/dL D-glucose addition in the culture medium. Short effect of elevated glucose levels was examined by addition of 183 mg/dL D-glucose addition in the culture medium for just one hour per day followed by changing the culture to standard medium (5.5 mM D-glucose) during the next 23-hours period. Cell proliferation was estimated by 2,3-Bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carbox-anilide (XTT) assay and phosphor-Erk western blot analysis. We found that coronary artery endothelial cell proliferation was significantly increased in the culture medium with the acute one-hour addition of 183 mg/dL D-glucose compared to the absence or chronic presence of 183 mg/dL D-glucose addition in the culture medium. In contrast, colon cancer cell proliferation was significantly increased in the continuous presence of 183 mg/dL D-glucose addition in the culture medium compared to the acute one-hour addition of glucose. The extent of Erk2 phosphorylation paralleled with the relative changes in cellular proliferation in both cell types. Taken together, these results suggested that continuous or transient high level of glucose exposure differentially effects coronary artery endothelial and human colon cancer cell proliferation

Effect of carbohydrate counting using bolus calculators on glycemic control in type 1 diabetes patients during continuous subcutaneous insulin infusion

This study examined the long-term efficacy of insulin pump therapy for type 1 diabetes patients when performed using carbohydrate counting with bolus calculators for one year. Twenty-two type 1 diabetes patients who had just started continuous subcutaneous insulin infusion were examined and divided into 2 groups: one that was educated about carbohydrate counting using bolus calculators (n=14) and another that did not use bolus calculators (n=8). After one year, the hemoglobin A1c levels of the patient group that used bolus calculators decreased persistently and significantly (P=0.0297), while those of the other group did not. The body weight, total daily dose of insulin, and bolus percentage of both groups did not change. Carbohydrate counting using bolus calculators is necessary to achieve optimal and persistent glycemic control in patients undergoing continuous subcutaneous insulin infusio

NR4A1 (Nur77) mediates thyrotropin-releasing hormone-induced stimulation of transcription of the thyrotropin β gene: analysis of TRH knockout mice.

Thyrotropin-releasing hormone (TRH) is a major stimulator of thyrotropin-stimulating hormone (TSH) synthesis in the anterior pituitary, though precisely how TRH stimulates the TSHβ gene remains unclear. Analysis of TRH-deficient mice differing in thyroid hormone status demonstrated that TRH was critical for the basal activity and responsiveness to thyroid hormone of the TSHβ gene. cDNA microarray and K-means cluster analyses with pituitaries from wild-type mice, TRH-deficient mice and TRH-deficient mice with thyroid hormone replacement revealed that the largest and most consistent decrease in expression in the absence of TRH and on supplementation with thyroid hormone was shown by the TSHβ gene, and the NR4A1 gene belonged to the same cluster as and showed a similar expression profile to the TSHβ gene. Immunohistochemical analysis demonstrated that NR4A1 was expressed not only in ACTH- and FSH- producing cells but also in thyrotrophs and the expression was remarkably reduced in TRH-deficient pituitary. Furthermore, experiments in vitro demonstrated that incubation with TRH in GH4C1 cells increased the endogenous NR4A1 mRNA level by approximately 50-fold within one hour, and this stimulation was inhibited by inhibitors for PKC and ERK1/2. Western blot analysis confirmed that TRH increased NR4A1 expression within 2 h. A series of deletions of the promoter demonstrated that the region between bp -138 and +37 of the TSHβ gene was responsible for the TRH-induced stimulation, and Chip analysis revealed that NR4A1 was recruited to this region. Conversely, knockdown of NR4A1 by siRNA led to a significant reduction in TRH-induced TSHβ promoter activity. Furthermore, TRH stimulated NR4A1 promoter activity through the TRH receptor. These findings demonstrated that 1) TRH is a highly specific regulator of the TSHβ gene, and 2) TRH mediated induction of the TSHβ gene, at least in part by sequential stimulation of the NR4A1-TSHβ genes through a PKC and ERK1/2 pathway

Real‐world evidence of population differences in allopurinol‐related severe cutaneous adverse reactions in East Asians: A population‐based cohort study

Abstract Allopurinol‐related severe cutaneous adverse reactions (SCARs) are strongly associated with HLA‐B*58:01, the allele frequency (AF) of which is largely different among East Asians. However, evidence of population differences in SCAR development and relevance of genetic and/or other risk factors in the real‐world remain unelucidated. This study aimed to evaluate population differences in allopurinol‐related SCAR incidence related to genetic and/or other risk factors among East Asians in the real‐world. A population‐based cohort study was conducted using claims databases from Taiwan, Korea, and Japan. New users of allopurinol (311,846; 868,221; and 18,052 in Taiwan, Korea, and Japan, respectively) were followed up to 1 year. As control drugs, phenytoin and carbamazepine were used. The crude incidence rate ratios (IRRs) of SCARs for allopurinol against phenytoin or carbamazepine were the highest in Taiwan (IRR, 0.62 and 1.22; 95% confidence interval [CI], 0.54–0.72 and 1.01–1.47, respectively), followed by Korea (IRR, 0.34 and 0.82; 95% CI, 0.29–0.40 and 0.77–0.87), and the lowest in Japan (IRR, 0.04 and 0.16; 95% CI, 0.02–0.08 and 0.09–0.29). This order was accordant with that of AF ratios (AFRs) reported of HLA‐B*58:01 against alleles responsible for phenytoin‐ or carbamazepine‐related SCARs. The IRRs were higher in patients with chronic kidney disease, females, and elderly. This study demonstrated population differences in the risk of allopurinol‐related SCAR development among East Asians based on genetic and other common risk factors. This finding will help to promote appropriate risk management for allopurinol‐related SCARs based on ethnic origins. Study Highlights WHAT IS THE CURRENT KNOWLEDGE ON THIS TOPIC? Allopurinol‐related severe cutaneous adverse reactions (SCARs) are strongly associated with HLA‐B*58:01, the allele frequency of which is largely different among East Asians. However, there is no direct real‐world evidence of population differences in SCAR development and the influence of genetic factors and/or other risk factors. WHAT QUESTION DID THIS STUDY ADDRESS? Do population differences in development of allopurinol‐related SCARs, depending on genetic factors and/or other risk factors, exist among three East Asians in the real‐world? WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE? The current analysis, based on comparisons of relative risks of SCAR incidence, provides real‐world evidence of population differences in allopurinol‐related SCAR development risk among East Asians, which was consistent with differences in reported HLA‐B*58:01 frequencies, as well as identifying chronic kidney disease, female gender, and old age as common risk factors. HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE? This study helps to promote appropriate risk management strategies for allopurinol‐related SCARs in the real‐world considering risk factors based on the patients’ ethnicity. Our approach is useful for evaluating population differences in the real‐world

Insulin pump therapy would be favored by pregnant women with diabetes

To evaluate retrospectively the satisfaction of continuous subcutaneous insulin infusion (CSII) compared to multiple daily infusions in Japanese women with diabetes mellitus (DM) during pregnancy, we examined 27 women with type 1 (n = 20) or type 2 (n = 6) diabetes mellitus or gestational diabetes (n = 1) who previously used CSII. Among these patients, 19 had used CSII during pregnancy, which accounted for 30 births. Questionnaires were retrospectively administered. The mean age of patients was 36.5 ± 7.0 years. The average birth weight was 3.1 ± 0.6 kg, with 62% of babies exhibiting complications. The satisfaction level of CSII for patients during pregnancy was 3.95 ± 0.26, whereas it was 1.84 ± 0.26 for multiple daily infusions (P < 0.001).CSII was generally viewed favorably by women with diabetes mellitus for glycemic management during pregnancy

HBA1C and mean glucose derived from short term continuous glucose monitoring (CGM) assessment do not correlate in patients with HBA1C >8

Aims: Optimum therapy for patients with diabetes depends on both acute and long-term changes in plasma glucose, generally assessed by HbA1c levels. However, the correlation between HbA1c and circulating glucose has not been fully determined. Therefore, we carefully examined this correlation when glucose levels were assessed by continuous glucose monitoring (CGM). Methods: 51 patients (70 % women, 30% male) were examined; among them were 28 type 1 patients with diabetes and 23 type 2 patients with diabetes. Clinically determined HbA1c levels were compared with blood glucose determined by CGM during a short time period. Results: Changes of HbA1c levels up to 8.0% showed a clear and statistically strong correlation (R=0.6713, P<0.0001) with mean blood glucose levels measured by CGM, similarly to that observed in the A1c-derived Average Glucose (ADAG) study where patients were monitored for a longer period. However, we found no statistical correlation (R=0.0498, P=0.8298) between HbA1c and CGM-assessed glucose levels in our patient population when HbA1c was greater than 8.0 % Conclusions: Short term CGM appears to be a good clinical indicator of long-term glucose control (HbA1c levels), however cautions should be taken while interpreting CGM data from patients with HbA1c levels above 8.0%. Over or under estimation of the actual mean glucose from CGM data could potentially increase the risks of inappropriate treatment. As such, our results indicate that a more accurate analysis of CGM data might be useful to adequately tailor clinical treatments